motor bearing lubrication?

I have bought a neu motor for a while and wonder is it necessary to lube the front and rear bearings?
I have seen a little amount of black grease has already been put out of the front bearing.
Have you done the lubrication or not ?
If yes, with what lubricant and how frequent?
Thanks.

I have a little bottle of synthetic bearing oil from boca and just add a drop to each bearing every so often...I buy the plastic end bell covers for my neu motors and that keeps the dirt out so the front bearing is the only one I oil from time to time.

[bdebde]

Some manufacturers say NOT to oil the motor bearings.

[FG101C]

I would like to try ceramics in my Tekno Neu.